Holocene crustal movement along the coast of western Kobe and the 1995 Kobe Earthquake, Japan

The 1995 Kobe (Hyogoken-Nanbu) Earthquake (Mj 7.2) in Japan, which has been attributed to the Nojima fault of the Rokko-Awaji fault system, resulted in vertical uplifts of 0.19 m at Tarumi and 0.07 m at Akashi, relative to Takasago. Here we evaluate these uplifts in the context of Holocene local tectonics derived from relative sea-level (RSL) records. For the purpose of this study, we estimate the Holocene relative uplift via a comparison study of observed and predicted sea-level variations along the traverse from Takasago to Tarumi and Akashi. These estimates are then applied to evaluate the uplift associated with the fault system responsible for the 1995 earthquake. As a rate of tectonic subsidence between 0.08 and 0.23 mm/yr corresponds well with the RSL index points determined for Takasago during the mid Holocene, uplift rates of 0.38-0.73 and 0.19-0.48 mm/yr are derived for Tarumi and Akashi, respectively, relative to Takasago. This suggests that the cumulated vertical uplift due to the Nojima fault activity, with a recurrence interval of approximately 2000 yr, may contribute at most 25% of the Holocene uplift proposed for the tectonically active coast of western Kobe.